Spinach

I grow a market garden in Northern Canada in a greenhouse.
This is the best spinach I have tried for the spring conditions here: warm shortish days, frosty nights.
The leaves of the first crop get to be 16 inches large, bigger if left longer.
I have trialed many others and this is the biggest, thickest for an early unheated greenhouse crop.
first planting is end of January - ready end of April.